Guess what. Everything humming now. Magnet attached well with plastic steel epoxy stick, winch fairly humming, and the damn thing won't count now. I guess because I drilled out half the old magnet to give the plastic steel something to lock into, (my previous attempts were epoxy onto a fairly smooth surface), it must have reduced the strength of the field (and yes, I did align the two fields), enough to end up too weak again damn-it. Now I'll have to fit a bigger magnet somehow. May cut a square recess out of the edge of the gypsy...? Other ideas anyone? It is beaut when it works - much better than paint which wears off, or ties or clips which get tatty and dirty and hard to see the colour of, and invisible at night.